1. Field of the Invention
The present invention relates generally to an assembly screw driver structure, and in particular a structure wherein the body of the screw driver may be concealed in the handle.
2. Description of the Prior Art
Conventional screw drivers comprise a handle and a body having its base secured to the front end of the handle. The front end of the body is the application end which is generally flat or cross shaped.
In order that the screw driver may be used with various kinds of screws, there is also a kind of assembly screw driver which includes the following two typical constructions:
The first kind is as shown in FIG. 1, in which the handle and the body are detachable so that the overall length of the screw driver is shortened when they are detached from each other. Generally speaking, this kind of screw driver construction has a number of bodies with different application ends, such as a flat or a cross application end. When in use, a body with a suitable application end is selected and the base of the body is assembled to the front end of the handle. This kind of assembly screw driver is already very common, and the manner of assembly is by means of a screw assembly device provided at the front end of the handle.
In the other kind of screw driver, the handle is fixedly attached to the body, but the front end of the body is an internal hexagonal sleeve for accommodating various kinds of short application heads, which consist of a base and an application end connected thereto. Certainly, each application head has a different application end.
The first kind of assembly screw driver described above can save storage space, but the cost of the various bodies for matching the handle is comparatively less economical than the second screw driver structure.
If one body is to match one handle, the first kind of screw driver structure has the advantage of easy storage since the handle and the body can be taken apart; however, the body may be easily lost after it is detached from the handle. In the second kind of screw driver, the space saved is very limited. Additionally, both structures have a common drawback, i.e., these kinds of assembly screw drivers cannot be used in a narrow space not wide enough to accommodate the overall length of the screw driver after assembly.